Principal Consultant - Fracture Testing, TWI (formerly The Welding Institute), Abington, Cambridge,
Pages: 11 Published: Jan 1995
A review of past studies shows that tests on specimens notched after welding can give overestimates of the fracture toughness that occurs at the tips of flaws present during welding. This situation results from locally intensified straining and ageing embrittlement (LISAE), which has been shown to trigger low stress brittle fractures in both notched and welded wide plate tension tests, and welded structures in service. Although the relative susceptibilities of steels to strain ageing embrittlement are sometimes assessed by testing bulk strained and aged samples, the results of such tests may be optimistic. A summary is given of work to develop a fracture toughness test method for LISAE. The new test will give increased confidence and accuracy in fracture assessments, be of use in selecting tough materials, and aid the development of materials that are resistant to LISAE.
Strain ageing embrittlement, LISAE, toughness, brittle fracture, base metal, weld metal, weld heat-affected zone, fracture mechanics, test methods
Paper ID: STP16394S